loess regression on each group with dplyr::group_by()

Question

Alright, I\'m waving my white flag.

I\'m trying to compute a loess regression on my dataset.

I want loess to compute a different set of points that plots a

Answer 1

You may have already figured this out -- but if not, here's some help.

Basically, you need to feed the predict function a data.frame (a vector may work too but I didn't try it) of the values you want to predict at.

So for your case:

fems <- fems %>% 
  group_by(CpG) %>% 
  arrange(CpG, AVGMOrder) %>% 
  mutate(Loess = predict(loess(Meth ~ AVGMOrder, span = .5, data=.),
    data.frame(AVGMOrder = seq(min(AVGMOrder), max(AVGMOrder), 1))))

Note, loess requires a minimum number of observations to run (~4? I can't remember precisely). Also, this will take a while to run so test with a slice of your data to make sure it's working properly.